0609160v1

related topics
{algorithm, log, probability}
{qubit, qubits, gate}
{states, state, optimal}
{information, entropy, channel}
{phase, path, phys}
{state, phys, rev}
{measurement, state, measurements}
{key, protocol, security}
{vol, operators, histories}
{alice, bob, state}
{cos, sin, state}

Optimal quantum circuits for general phase estimation

W. van Dam, G. M. D'Ariano, A. Ekert, C. Macchiavello, M. Mosca

abstract: We address the problem of estimating the phase phi given N copies of the phase rotation gate u(phi). We consider, for the first time, the optimization of the general case where the circuit consists of an arbitrary input state, followed by any arrangement of the N phase rotations interspersed with arbitrary quantum operations, and ending with a POVM. Using the polynomial method, we show that, in all cases where the measure of quality of the estimate phi' for phi depends only on the difference phi'-phi, the optimal scheme has a very simple fixed form. This implies that an optimal general phase estimation procedure can be found by just optimizing the amplitudes of the initial state.

oai_identifier:
oai:arXiv.org:quant-ph/0609160
categories:
quant-ph
comments:
4 pages, 3 figures
arxiv_id:
quant-ph/0609160
created:
2006-09-20

Full article ▸

related documents
0207108v1
0403071v1
0303074v1
0508156v3
9812057v1
0208112v1
9702057v1
0209148v1
0206066v1
0308016v1
0612052v2
0406104v1
0608156v1
0609166v1
0401067v2
0403160v1
0612123v2
0701079v1
0406077v1
0501093v1
0403188v1
0407120v1
0412083v1
0610258v1
0507194v1